Users can upload new journalists

Trello: https://trello.com/c/v0ua84y2/88-enable-csv-journalist-uploads

![journalist-import](https://cloud.githubusercontent.com/assets/4560985/5345328/fa3a743a-7ee4-11e4-9e54-31143dfb1940.gif)

Can this migration be reversed? Does `rake db:rollback` work?